The dielectric theory of HREELS, a short survey

The dielectric theory of high-resolution electron-energy-loss spectroscopy (HREELS) is now more than 30-years-old [Phys. Rev. Lett. 26 (1971) 229]. Since the very beginning, this theory revealed to be a great success, for it provided immediately a quantitative description of the energy-loss spectra obtained in specular reflection by the newly-developed surface spectrometers [Phys. Rev. Lett. 24 (1971) 1416]. First designed to deal with simple crystalline materials, the Lucas-Sunjic theory has been progressively adapted to more complex systems. A brief, comprehensive presentation of the theory is given together with a short description of its latest developments. The success of the theory is illustrated with recent examples of HREELS experiments performed on GaAs/AlGaAs heterostructures, C ₆₀ fullerene films, and carbon nanosystems.